Most people researching peptide dosing assume the hard part is sourcing the peptide. It isn’t. The hard part is converting a target dose in micrograms into a precise line on a tiny insulin syringe after you’ve added a specific volume of bacteriostatic water to a lyophilized vial. Get that math wrong by a factor of 1,000 (mg versus mcg confusion is more common than anyone admits) and the error is not minor. These seven tools exist for exactly that problem.
1. FormBlends Peptide Calculator
Best for: Anyone who needs to see the math, not just the answer
The reconstitution math behind peptide dosing is straightforward algebra, but most tools hide it behind a black box. This one shows the full calculation on screen so you can confirm every step yourself.
You enter three things: the amount of peptide in the vial, how much bacteriostatic water you added, and your target dose per injection. The tool returns the concentration per milliliter, the exact number of units to draw, and the total number of doses the vial contains. A visual fill bar shows where that draw lands on the syringe barrel.
A few specifics worth knowing. It defaults to U-100 (the standard 100-units-per-mL insulin syringe) but also handles U-50 and U-40 syringes, which occasionally appear in clinical settings. It manages the mg-to-mcg conversion automatically, which matters because BPC-157 and similar healing peptides are typically dosed in the 250 to 500 mcg range, while vials are often labeled in mg. One-tap presets cover BPC-157 at 5 mg and 10 mg, TB-500 at 5 mg, ipamorelin at 10 mg, tesamorelin at 2 mg, and a 50 mg GLP-1 option.
No account required. No paywall. The same calculator lives inside the FormBlends mobile app (iOS and Android), which adds a 55-compound reference library, a dose log, and an injection-site rotation map.
One important clarification: the tool does not tell you what dose to take. You supply the dose, it tells you how to measure it. That distinction matters.
2. PeptideFox
Found at peptidefox.com, this calculator supports more than 30 named peptides and includes something the others mostly skip: guidance on how much BAC water to add so your draw lands on a clean unit mark. Minimizing rounding error at the syringe level is genuinely useful. A visual reference guide accompanies the output.
3. PeptideDeck
Simple three-field entry. You put in the vial’s total mg, the volume of BAC water you added in mL, and your target dose in mcg. PeptideDeck returns the concentration and the exact volume to draw in both mL and insulin units. No extra features, no account. Clean and fast.
4. peptidereconstitutecalculator.com
Narrowly focused on BPC-157. If that’s the only compound you’re working with, the specificity is a feature rather than a limitation. Outputs are framed in U-100 units, and the mcg-to-units conversion is clearly labeled.
5. MyPeptideMatch
Covers BPC-157, TB-500, semaglutide, tirzepatide, and several other injectables including GLP-1 class compounds. Free to use. Particularly relevant for people working with weight-management peptides alongside the more common healing compounds.
6. LeadWest Medical
A calculator with a slightly clinical presentation, covering retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. The range of compounds is broader than most tools in this category.
7. Outliyr
Covers a similar compound list to LeadWest (BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and GLP-1 class peptides) with a wellness-oriented editorial context around it. Useful if you want more background reading alongside the numbers.
One Thing True for All of Them
A U-100 syringe holds 100 units per mL. Ten units equals 0.1 mL. That relationship never changes. What changes is the concentration in your vial, which depends entirely on how much water you added during reconstitution. More water means more units drawn per dose, not a larger dose. Every calculator on this list is doing the same arithmetic around that fixed ratio.
Common Questions
Why do these calculators ask for BAC water volume instead of just the peptide dose?
The water volume you added is what determines concentration, and concentration is the only variable that changes between vials. Two people with the same 5 mg BPC-157 vial can end up drawing completely different unit counts if they reconstituted with different amounts of bacteriostatic water. The calculator needs both numbers to give you a meaningful answer.
Does it matter which syringe type I use when entering values into tools like FormBlends or PeptideDeck?
Yes, and this is where errors happen. A U-100 syringe and a U-40 syringe look nearly identical but their unit markings represent different volumes. FormBlends explicitly lets you switch between U-100, U-50, and U-40. PeptideDeck outputs both mL and insulin units, so you can cross-check against whichever barrel you’re holding.
PeptideFox suggests a specific BAC water volume rather than accepting whatever I used. Why would that be helpful?
If you add a volume that produces an awkward concentration, your draw might land between unit marks on the syringe, forcing a rounding call. PeptideFox works backward from clean unit increments to suggest a water volume that makes the measurement exact. That removes one source of dosing imprecision before you even open the vial.
Can I use peptidereconstitutecalculator.com for semaglutide or GLP-1 compounds, or is it only for BPC-157?
That tool is narrowly built for BPC-157 only. For semaglutide, tirzepatide, or retatrutide, you need a different option. MyPeptideMatch covers semaglutide and tirzepatide specifically. LeadWest Medical includes retatrutide. FormBlends has a 50 mg GLP-1 preset built into its one-tap options.
If I already know my dose in mcg, what is the minimum information any of these calculators actually needs from me?
Three values: total peptide in the vial (in mg), volume of BAC water added (in mL), and your target dose per injection (in mcg). Every calculator on this list takes those three inputs. The mg-to-mcg conversion is handled automatically by most of them, including FormBlends and PeptideDeck, so you do not need to convert manually before entering the vial amount.
A Note Before You Use Any of These
These tools calculate measurement. They do not establish what your dose should be. Before injecting any compound, get that guidance from a licensed medical provider who has reviewed your specific situation. A calculator that gives you the right number of units is only useful if the underlying dose was appropriate to begin with.
Sources
- U-100 syringe unit/volume standard: FDA insulin syringe labeling guidelines
- peptidereconstitutecalculator.com (public tool, verified 2025)
- peptidefox.com (public tool, verified 2025)
- PeptideDeck (public tool, verified 2025)
- Outliyr.com peptide calculator (public tool, verified 2025)
- LeadWest Medical calculator (public tool, verified 2025)
- MyPeptideMatch (public tool, verified 2025)
